Method and apparatus for positioning

Abstract

Provided is a positioning method performed by a user equipment (UE). The positioning method includes receiving reference signals from a plurality of base stations; acquiring phase difference information depending on a wavelength of at least one subcarrier among subcarriers included in the reference signals; calculating first estimated coordinates of the UE based on first phase difference information depending on a wavelength of a first subcarrier among the subcarriers; and calculating a first travel distance difference between the reference signals from the first estimated coordinates and estimating integer ambiguity of a second phase difference depending on a wavelength of a second subcarrier from the first travel distance difference.

What is claimed is: 
     
       1. A positioning method performed by a user equipment (UE), the positioning method comprising:
 receiving reference signals from a plurality of base stations; 
 acquiring phase difference information depending on a wavelength of at least one subcarrier among subcarriers comprised in the reference signals; 
 calculating first estimated coordinates of the UE based on first phase difference information depending on a wavelength of a first subcarrier among the subcarriers; 
 calculating a first travel distance difference between the reference signals from the first estimated coordinates and estimating integer ambiguity of a second phase difference depending on a wavelength of a second subcarrier from the first travel distance; difference; 
 calculating k th  estimated coordinates based on k th  phase difference information depending on a wavelength of k th  subcarrier; and 
 calculating a k th  travel distance difference from the k th  estimated coordinates and estimating integer ambiguity of a (k+1)-th phase difference depending on a wavelength of a (k+1)-th subcarrier from the k th  travel distance difference, 
 wherein the calculating of the k th  estimated coordinates and the estimating of the integer ambiguity of the (k+1)-th phase difference is repeated until a preset termination condition is met, and k denotes a natural number. 
 
     
     
       2. The positioning method of  claim 1 , wherein the wavelength of the (k+1)-th subcarrier is shorter than the wavelength of the k th  subcarrier. 
     
     
       3. The positioning method of  claim 1 , further comprising:
 acquiring phase difference information depending on a wavelength of a carrier comprised in the reference signals; 
 estimating integer ambiguity of a phase difference depending on the wavelength of the carrier based on a travel distance difference that is acquired from a phase difference depending on a wavelength of a subcarrier having a longest wavelength among the subcarriers; and 
 calculating a position of the UE based on a phase difference depending on the wavelength of the carrier. 
 
     
     
       4. The positioning method of  claim 1 , wherein the calculating of the k th  estimated coordinates comprises:
 calculating initial estimated coordinates of the UE from the k th  phase difference information; and 
 modifying the initial estimated coordinates through an iterative operation and calculating the k th  estimated coordinates. 
 
     
     
       5. The positioning method of  claim 4 , wherein the modifying of the initial estimated coordinates and the calculating of the k th  estimated coordinates comprises calculating an n th  travel distance difference between the reference signals from n th  estimated coordinates and calculating (n+1)-th estimated coordinates modified from the n th  estimated coordinates based on an error between the n th  travel distance difference and a travel distance difference corresponding to the k th  phase difference, and
 the calculating of the n th  travel distance difference and the calculating of the (n+1)-th estimated coordinates is repeated until a preset termination condition is met. 
 
     
     
       6. The positioning method of  claim 5 , wherein the calculating of the n th  travel distance difference and the calculating of the (n+1)-th estimated coordinates is repeated until an error between the n th  estimated coordinates and the (n+1)-th estimated coordinates becomes to be less than a preset tolerance. 
     
     
       7. The positioning method of  claim 5 , wherein the (n+1)-th estimated coordinates depend on a product of a partial differential coefficient matrix for a travel distance difference between the reference signals and the error between the n th  travel distance difference and the travel distance difference corresponding to the k th  phase difference. 
     
     
       8. The positioning method of  claim 1 , wherein the acquiring of the phase difference information depending on the wavelength of at least one subcarrier among the subcarriers comprises:
 acquiring a first sample vector based on received data of a first reference signal and acquiring a second sample vector based on received data of a second reference signal; 
 calculating a first phase vector and a second phase vector by performing an inner product of a discrete Fourier transform (DFT) coefficient vector with respect to each of the first sample vector and the second sample vector; 
 calculating a third phase vector by conjugating a 1-1 partial vector corresponding to a first portion of the first phase vector and a 1-2 partial vector corresponding to a second portion of the first phase vector; 
 calculating a fourth phase vector by conjugating a 2-1 partial vector corresponding to a first portion of the second phase vector and a 2-2 partial vector corresponding to a second portion of the second phase vector; and 
 acquiring phase difference information depending on the wavelength of at least one subcarrier among the subcarriers by conjugating the third phase vector and the fourth phase vector. 
 
     
     
       9. The positioning method of  claim 3 , wherein the acquiring of the phase difference information depending on the wavelength of the carrier comprised in the reference signals comprises:
 acquiring a first sample vector based on received data of a first reference signal and acquiring a second sample vector based on received data of a second reference signal; 
 calculating a first phase vector and a second phase vector by performing an inner product of a DFT coefficient vector with respect to each of the first sample vector and the second sample vector; and 
 acquiring phase difference information depending on the wavelength of the carrier from a conjugate product of the first phase vector and the second phase vector. 
 
     
     
       10. A positioning apparatus comprising:
 a communicator; and 
 a processor configured to connect to the communicator, 
 wherein the processor is configured to perform a process of receiving reference signals from a plurality of base stations, a process of acquiring phase difference information depending on a wavelength of at least one subcarrier among subcarriers comprised in the reference signals, a process of calculating first estimated coordinates of a user equipment (UE) based on first phase difference information depending on a wavelength of a first subcarrier among the subcarriers, and a process of calculating a first travel distance difference between the reference signals from the first estimated coordinates and estimating integer ambiguity of a second phase difference depending on a wavelength of a second subcarrier from the first travel distance difference, and 
 wherein the processor is configured to further perform a process of calculating k th  estimated coordinates based on k th  phase difference information depending on a wavelength of a k th  subcarrier, and a process of calculating a k th  travel distance difference from the k th  estimated coordinates and estimating integer ambiguity of a (k+1)-th phase difference depending on a wavelength of a (k+1)-th subcarrier from the k th  travel distance difference, and 
 
       the process of calculating the k th  estimated coordinates and the process of estimating the integer ambiguity of the (k+1)-th phase difference is repeated until a preset termination condition is met, and k denotes a natural number. 
     
     
       11. The positioning apparatus of  claim 10 , wherein the wavelength of the (k+1)-th subcarrier is shorter than the wavelength of the k th  subcarrier. 
     
     
       12. The positioning apparatus of  claim 10 , wherein the processor is configured to further perform a process of acquiring phase difference information depending on a wavelength of a carrier comprised in the reference signals, a process of estimating integer ambiguity of a phase difference depending on the wavelength of the carrier based on a travel distance difference that is acquired from a phase difference depending on a wavelength of a subcarrier having a longest wavelength among the subcarriers, and a process of calculating a position of the UE based on a phase difference depending on the wavelength of the carrier. 
     
     
       13. The positioning apparatus of  claim 10 , wherein the process of calculating the k th  estimated coordinates comprises:
 a process of calculating initial estimated coordinates of the UE from the k th  phase difference information; and 
 a process of modifying the initial estimated coordinates through an iterative operation and calculating the k th  estimated coordinates. 
 
     
     
       14. The positioning apparatus of  claim 13 , wherein the process of modifying the initial estimated coordinates and calculating the k th  estimated coordinates comprises:
 a process of calculating an n th  travel distance difference between the reference signals from n th  estimated coordinates; and 
 a process of calculating (n+1)-th estimated coordinates modified from the n th  estimated coordinates based on an error between the n th  travel distance difference and a travel distance difference corresponding to the k th  phase difference, and 
 the process of calculating the n th  travel distance difference and the process of calculating the (n+1)-th estimated coordinates is repeated until a preset termination condition is met. 
 
     
     
       15. The positioning apparatus of  claim 14 , wherein the process of calculating the n th  travel distance difference and the process of calculating the (n+1)-th estimated coordinates is repeated until an error between the n th  estimated coordinates and the (n+1)-th estimated coordinates becomes to be less than a preset tolerance. 
     
     
       16. The positioning apparatus of  claim 14 , wherein the (n+1)-th estimated coordinates depends on a product of a partial differential coefficient matrix for a travel distance difference between the reference signals and the error between the n th  travel distance difference and the travel distance difference corresponding to the k th  phase difference. 
     
     
       17. The positioning apparatus of  claim 10 , wherein the process of acquiring the phase difference information depending on the wavelength of at least one subcarrier among the subcarriers comprises:
 a process of acquiring a first sample vector based on received data of a first reference signal and acquiring a second sample vector based on received data of a second reference signal; 
 a process of calculating a first phase vector and a second phase vector by performing an inner product of a discrete Fourier transform (DFT) coefficient vector with respect to each of the first sample vector and the second sample vector; 
 a process of calculating a third phase vector by conjugating a 1-1 partial vector corresponding to a first portion of the first phase vector and a 1-2 partial vector corresponding to a second portion of the first phase vector; 
 a process of calculating a fourth phase vector by conjugating a 2-1 partial vector corresponding to a first portion of the second phase vector and a 2-2 partial vector corresponding to a second portion of the second phase vector; and 
 a process of acquiring phase difference information depending on the wavelength of at least one subcarrier among the subcarriers by conjugating the third phase vector and the fourth phase vector. 
 
     
     
       18. The positioning apparatus of  claim 12 , wherein the process of acquiring the phase difference information depending on the wavelength of the carrier comprised in the reference signals comprises:
 a process of acquiring a first sample vector based on received data of a first reference signal and acquiring a second sample vector based on received data of a second reference signal; 
 a process of calculating a first phase vector and a second phase vector by performing an inner product of a DFT coefficient vector with respect to each of the first sample vector and the second sample vector; and 
 a process of acquiring phase difference information depending on the wavelength of the carrier from a conjugate product of the first phase vector and the second phase vector.